The machining of the edges of sheets with edge millers is a generally well-known process. In such cases the loaded cutter length is constant as a function of the strip thickness and the advance position of the cutters. In machining with high power, this results in a concentrated cutting load, that has the effect of reducing the working life. One possibility for improving this situation consists of lengthening the active cutting length.
Milling units with cylindrical cutter units that are mounted on their longitudinal axes are disclosed by European Patent No. 0 038 923 and elsewhere. The rotating cutting tool described in this publication is a face miller for sheet metal edges in which the machined surface is perpendicular to the axis of rotation of the milling unit. The axes of rotation of the cutters of this known face miller are arranged parallel to the working surface. Consequently, the fronts of the cylindrical cutters are used for the chip-removing tool surfaces. However, this known face miller cannot be used under conditions of practical application, and one of the main reasons for this is the excessively low achievable rate of milling, that results from small contact lengths corresponding to the geometric conditions. Thus, the machining conditions prevailing with this known cutting tool and thus the chipping efficiency are unfavorable.
An edge miller of the type mentioned initially is disclosed essentially in German patent application Disclosure No. 2 735 283. In this case there is a solid, nonrotating screw connection between the milling unit and the circular cutters, so that it is impossible for the cutters to rotate during the contact. For this reason, because of the concentrated load on the cutter edges, only very short lifetimes are possible in high-output applications. Another substantial drawback of this known edge miller is the fact that the machining of the V-shaped diagonal cut running on the centerline of the plate has to be done either with two sloping millers or with a two-part miller consisting of upper and lower cutters. In both cases the chipping conditions in the area of the centerline of the plate are extremely unfavorable, since in this case the value of the rake angle is equal to zero in each case with the contact points of the cutting wheels in the area of the cutting lines. Consequently, this known edge miller is practically unusable for machining metallic workpiece.